PROJECT SUMMARY The purpose of this grant application is to request funds to partially support planning, organizing and hosting HIV Research for Prevention 2018: Vaccine, Microbicide and ARV-based Prevention Science Conference (HIVR4P), international conference. HIVR4P 2018 is the third in this conference series, the world's first and only scientific meeting dedicated to biomedical HIV prevention research. Its primary goals are to help create opportunities for trans-disciplinary interactions in biomedical prevention research; expand discussions of crosscutting issues as new HIV prevention options are developed, and increase coordination and communication among international groups. The pursuit of effective biomedical HIV prevention options has progressed further and faster in the last few years than at any time since the epidemic began. Breakthroughs in vaccines, ARV-based microbicides, monoclonal antibody injections, PrEP, treatment for prevention and other prevention technologies create new opportunities to reduce the impact of the global epidemic. This progress also brings opportunity for scientific debate and creates new challenges as we continue to move HIV biomedical prevention research forward. Most importantly, these advances teach us that effective HIV prevention will require a combination of approaches. This third biennial meeting will take place 22?25 October 2018 at the Madrid Marriott Auditorium Hotel & Conference Center, in Madrid, Spain. This international conference will once again bring together researchers, advocates, clinicians, policy makers, private sector partners and public health experts to present, discuss, and debate the latest research in ARV-based prevention, vaccines and related areas of HIV prevention. It will build on and link to the successes of the previous conferences. The 2018 conference will continue to drive greater coordination, cross-fertilization and increased collaboration. It will also provide a forum to address cross-cutting issues, emphasizing the importance of combination prevention, and it will break down any existing research siloes between different prevention technologies. HIVR4P 2018 will have a significant impact on the advancement of scientific research in unique prevention areas with the potential to make significant progress in the prevention of HIV infection. The conference will attract between 1,400?1,500 members of the HIV prevention community and will provide 200 full and 100 partial scholarships as well as subsidized registration rates for early-career and lower-middle income country (LMIC) scientists. Information presented at the conference will be disseminated to give free, worldwide access to all who are unable to attend in person. Peer-reviewed abstracts will be published online in an open access journal, and posters will be available online as e-posters. All sessions will be available as webcasts and daily rapporteur reports summarizing scientific advances will be posted on the conference website.